Mantle for gyratory crushers and means for securing it



O. C. GRUENDER MANTLE FOR GYRATORY CRUSHERS AND MEANS FOR SECURING IT Feb. 15, 1944.

Filed June 27, 194i 5 Sheets-Sheet 1 q I n frzverzzor 050a?- 6'. Qruender.

Feb. 15, 1944.. 0, Q GRUENDER 2,341,544

MANTLE FOR GYRATORY GRUSHERS AND MEANS FOR SECURING IT Filed June 27, 1941 3 Sheets-Sheet 2 raven i0 r Feb. 15, 1944. o. c. GRUENDER 2,341,544

MANTLE FOR GYRATQRY QRUSHERS ANDMEANS FOR SECURING IT Filed June 27, 1941 3 Sheets-Sheet 3 Int/6721507".

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MANTLE FOR GYRATORY CRUSHERS AND MEANS FOR SECURING IT Oscar C. Gruender, Milwaukee, Wis., asslgnor to Nordberg Manufacturing Company, Milwaukee. Wis., a'corporatlon of Wisconsin Application June 2'7. 1941, Serial No. 400,033

22 Claims.

My invention relates to an improvement in wearing parts for gyratory crushers and has for one purpose the provision of an improved mantle for such a crusher which shall be quick and easy to apply and remove and which shall be selftightening in use.

Another purpose is the provision of improved means for securing such a mantle in position.

Another purpose is the provision of an improved mantle in which part of the locking means are formed integrally with the mantle.

Another purpose is the provision of a mantle of manganese steel or the like in which the locking means include a portion of the mantle adapted to yield or compensate for peening or stretching of the body of the mantle during use.

Another purpose is the provision of an improved mantle adapted to prevent relative movement of the mantle and of the soft metal packing or backing which is employed with it.

Other purposes will appear from time to time in the course of the specification and claims.

I illustrate my invention more or less diagrammatically in the accompanying drawings wherein:

Fig. 1 is a vertical section illustrating one of the improved mantles in position;

Fig. 2 is a section on the line 2-2 of Fig. 1;

Fig. 3 is a plan view of one of the mantles;

Fig. 4 is a section on the line 44 of Fig. 3;

Fig. 5 is a partial plan view illustrating a variant form of the mantle;

Fig. 6 is a vertical axial section through a variant locking means; and

Fig. 7 is a section on the line 1--'| of Fig. 6.

Like parts are indicated by lik symbols throughout the specification and drawings.

My mantle is illustrated in connection with a so-called gyratory cone crusher. The crusher itself does not form part of the present invention and is not indicated in complete detail. I illustrate, however, a cone or head I, which is mounted upon an upright portion 2, fixed on any suitable crusher base not herein shown. The portion 2 is in the form of a cylindrical member fixed on the crusher frame. Rotatable thereabout is an eccentric sleeve 3, which may be rotated by any suitable means not herein shown. I may employ suitable bearing liners or sleeves 3a and 3b.

The inner wall of the eccentric aperture of the sleeve 3 is in bearing relationship with the cylindrical exterior surface of the member 2. The

outer surface of the eccentric sleeve 3, which is also cylindrical but inclined to the inner surface, is in bearing relationship with a corresponding inner cylindrical surface of the head i.

The vertical center line of the crusher is ill-- dicated at X. The head I is generally conic, but has a transversely extending top portion 4, which continues upwardly in a stem 5, herein shown as generally cylindrical.

8 is a mantle of generally conic form. It has a top screw thread I, in mesh with a corresponding thread 8 on the lower end of a locking sleeve 9, mounted on the stem 5, and held against upward movement by the wedge or key I0, which passes through an aperture Illa in the stem ll. ii is any suitable securing screw which prevents endwise movement of the key l0. i2 is any suitable ieed distributing plate, which may be mounted on or form part of the above described structure.

Y indicates the center line or axis of the head. It will be observed that the lines X and Y intersect at the point Z. It will be understood that, when the eccentric sleeve 3 is rotated, the head and with it the mantle dare gyrated in such fashion as to exert a crushing action against the below described bowl liner.

l4 indicates any suitable packing or backing of soft metal, such as zinc, between the outer face of the wall I and the inner face of the mantle 6. The mantle 6 is provided with a lower conic surface I5, which abuts against a corresponding surface at a lower portion of the head I. Above the contact between the surface I5 and the head I, the mantle 8 is outwardly recessed, as at It, and, if desired. the head may be inwardly recessed, as at ll. Thus. a space is provided for the packing or backing ll of zinc or the like.

In order to prevent relative rotation of this packing and the mantle, I may provide any suitable means to maintain an interpenetration of the two metals. I illustrate, for example, a plurality of recesses l8. However, it will be realized that other means, such as a mere roughening of the inner wall of the mantle, may be employed. What is essential is that there shall be some gripping or interpenetration whereby, when the mantle moves in relation to the head, the packing or backing of zinc or the like moves with it.

It will be observed that the thread 1 extends about an arc of 360 degrees. In the drawings, as in Fig. i, the thread is shown as extending about precisely 360 degrees of arc. It will be understood, however, that it may extend somewhat more or somewhat less than 360 degrees. A variety of forms of thread may be employed. but I find it desirable to have the top or thrusthis face of the thread generally fiat and generally perpendicular to the axis of the nut or sleeve 9.

In the form of Fig. 5 I illustrate a thread la, which may be identical with the thread 1 of Fig. 4, but which is interrupted at a plurality of points, as at lb.

In connection with both forms of the device, it will be understood that I find it preferable to employ manganese steel, a metal which is highly resistant to wear and which can stand up under the crushing impacts of a gyratory crusher. One characteristic of this metal, however, is that it peens or stretches under use. This peening or stretching or distortion of the mantle tends to throw a heavy stress on whatever locking means are employed. I find it desirable, therefore, to provide locking means which may give or flex slightly, in order to compensate for this stretching action. I, therefore. provide a thread which has a lateral inward extension from the body of a length sufficient to enable it to flex somewhat in relation to the body as a whole, whereby a thread 8, of steel or other metal which may have a different characteristic than manganese steel, will not be ruptured. In other words, after a period of use during which the mantle may stretch and peen, and an upward thrust of the metal of which the mantle is composed may result, this thrust, instead of rupturing or distorting the thread 8 or the sleeve 9, will cause a slight but suflicient flexure of the thread i.

I may find it advantageous under some circumstances to permit various portions of the thread an independent flexure. This is the purpose of the interruptions lb shown in Fig. 5.

I illustrate the thread of the mantle as being a left-hand thread. While I illustrate a lefthand thread, this is not compulsory and I could employ a right-hand thread with equal effect. The pitch of the thread is so related to the direction of movement of the head that whatever rotation is given to the head in the course of the crushing operation is effective to tighten the mantle.

Referring to the device as a whole, 25 indicates a crushing bowl, which may form part of or be mounted on any suitable crushenframe, not herein shown. It includes a generally cylindrical outer wall 25, and an upwardly and inwardly inclined inner wall 2i, and a plurality of generally vertical ribs 28, which may terminate inwardly of a top supporting face 29 of the wall 21, the supporting face 29 being generally horizontal.

30 is a rotatable locking nut, having an inner locking thread 3|, and a plurality of upwardly extending lugs 32, which may be employed for rotating the locking nut 39 and for thereby tightening the below described bowl liner 33. It is'shown as having an inner face 33a, which is generally conic and which, with the outer face of the mantle 3, defines a crushing cavity. If desired, the lower portion of the face may be at a more obtuse angle, as at 35, and is shown as in parallelism with the opposed face of the mantle 6. That is to say, the opposed faces are generally parallel when the mantle 6 is at its closest or crushing approach to the bowl liner 33. The liner 33 is provided with a lower conic outer face 35, which is adapted for a metal to metal contact with an opposed face 38 of the wall 21. Above such zone of contact the liner 33 is inwardly reduced, as at 31, to give room for a body of soft metal 38 of zinc or the like.

' of the order of 360 degrees.

Relative rotation of the body of zinc and the liner 33 may be prevented by any suitable means. Preferably integral with the outer face of the bowl liner and herein shown as at the top of the bowl liner is a thread 40, which preferably extends about the liner through an angle of arc It is shown as Precisely 360 degrees, but it will be understood that it may be made somewhat more or somewhat less than 360 degrees under some circumstances.

While a variety of form of thread may be used, I find it advantageous to have a form of thread with a plane or substantially plane bottom face, as at ti. That is to say, it is fiat, although, of course, it conforms to a spiral and may abut snugly against the corresponding fiat upper face 62 of the thread 3| of the locking nut 30. It will be observed that the parts are so proportioned that the inner edge of the thread 3| is spaced substantially outwardly from the opposed wall of the bowl liner 33. I find it advantageous to make the bowl liner, like the mantle, of manganese steel or its equivalent.

Referring to the form of Fig. 6, I illustrate a lower locking nut 50, having a thread 5|, which engages the thread I of the mantle 6. This nut fits around the lower part of the stem or extension 5 of the head and is held against rotation by any suitable means, such as the key 52. The upper nut 53 is threaded to a, screw threaded upper portion 5a of the stem 5. This upper nut 53 bears against the top of the lower nut 50. The upper nut 53 is secured against rotation by any suitable locking means.

.1 illustrate, for example, a locking member 54, which has a key projection 55 fitting in a slot 55 in the upper stem projection 5a. The looking member 54 has a series of projections 51 on the outside which fit into cored recesses 58 in the upper nut 53, and a block of wood or equivalent material 59 may be inserted between the top of the member 54 and the feed plate 60. The feed plate 66 is secured to the top of the upper nut 53 by the threaded bolt 6!.

It will be realized that, whereas I have described and illustrated a practical and operative device, nevertheless many changes may be made in the size, shape, number and disposition of parts without departing from the spirit of my invention. I therefore wish my description and drawings to be taken as in a broad sense illustrative or diagrammatic, rather than as limiting me to my precise showing.

For example, it will be understood that, whereas I have shown a specific type of thread with a flat top, I may employ a variety of shapes of thread, whether standard or of special design.

The use and operation of my invention are as follows:

No material has so far been found to equal manganese steel for the wearing parts of gyratory crushers of the type herein shown. Manganese steel possesses extreme toughness and wear-resisting characteristics. It has the peculiar characteristic of flowing or deforming under the pounding or impact normal to the crushing operation. It is, therefore, a difiicult problem to provide means for adequately holding the mantles in position and to provide for their ready removal for replacement.

Where a locking means at the top of the head is provided in direct bearing contact with the body of the mantle, the deformation of the mantle in the course of time may create an excess upward thrust against the locking means suflicient to bend or distort the threads and finally break it. This is a condition which is not infrequently met in the field.

I find it desirable to interpose between the locking means and the body of the mantle means effective to maintain a locking thrust of the mantle downwardly against the head but which will not transmit to the locking means any undesired thrust caused by the deformation or peening or stretching of the mantle in the course of its use on the machine. In the present device I flnd it convenient to make this thrust transmitting means integral with or part of the mantle itself, which can be cast unitary with the mantle. This is a matter of convenience rather than necessity, and a takeup means of the type herein shown could be interposed between the top of the mantle and the locking nut or looking sleeve thereabove.

Referring in detail to the mantle herein described and shown, I employ a mantle body that is of manganese steel, which has adjacent its upper edge a single left-hand thread of about 360 degrees of arc. This is not a thread formed in the mantle so much as a thread which extends inwardly from the mantle. It will be. understood that the thread is not cut in the mantle, and the mantle is not weakened by the thread, the thread 1 extending laterally from the mantle itself, to a distance sufficient to provide the possibility of flexure of the thread to relieve an undesired upward thrust against the thread 8 of the locking nut or sleeve 9. It will be noted also that the outer edge of the thread 8 of the nut does not extend to the inner face of the mantle, but is spaced substantially inwardly therefrom.

I find it also desirable to have the opposed faces of the two threads generally flat and generally at right angles to the axis of the head. Under some circumstances it is advantageous to permit the individual parts of the thread to flex individually, and I obtain this result by interrupting the thread at spaced points, as shown at 1b in Fig. 5.

It will be understood that, whereas I have described and shown a left-hand thread, this is because of the relationship between the direction of drive or the direction of gyration of the crushers with which the mantle is employed. In other words, whatever may be the direction of rotation of the eccentric sleeve or means which gyrates the head, the thread of the mantle is so pitched as to provide a self-tightening effect. It will be understood that the thread. therefore,

not merely cooperates in holding the mantle cated cone and having an exterior generally conic crushing face and an interior generally conic head engaging face, the thickness of said body being generally uniform from top to bottom thereof, and an integrally formed locking and stress relieving element, in the form of a thread located adjacent the top of said body and extending laterally inwardly therefrom into the central aperture at the top of the body, the radial extension of said thread inwardly from the body being sufllcient to permit a flexure of the thread in response to the tendency of the body to peen or deform under crushing stress, and substantially exceeding the thickness of the thread.

2. In a self tightening mantle for the head of a gyratory crusher, a unitary hollow body of a metal having the characteristics of manganese steel as to deformation under impact, said body having the general form of an open topped truncated cone and having an exterior generally conic crushing face and an interior generally conic head engaging face, the thickness of said body being generally uniform from top to bottom thereof, and an integrally formed locking and stress relieving element, in the form of a thread located adjacent the top of said body and extending laterally inwardly therefrom into the central aperture at the top of the body, the radial extension of said thread inwardly from the body being sufficient to permit a flexure of the thread in response to the tendency of the body to peen or deform under crushing stress, and substantially exceeding the thickness of the thread, said thread extending through an angle of arc of the order of 360 degrees only, whereby the entire thread may flex under strain.

3. In a self tightening mantle for the head of a gyratory crusher, a unitary hollow body of a metal having the characteristics of manganese steel as to deformation under impact, said body.

having the general form of an open topped truncated cone and having an exterior generally conic crushing face and an interior generally conic head engaging face, the thickness of-said body being generally uniform from top to bottom thereof, and an integrally formed locking and stress relieving element, in the form of a thread located adjacent the top of said body and extending laterally inwardly therefrom into the central aperture at the top of the body, the radial extension of said thread inwardly from the body being suflicient to permit a flexure of the thread in response to the tendency of the body to peen or deform under crushing stress, and substantially exceeding the thicknessof the thread, the upper surface of said thread being generally horizontal in radial cross section and generally perpendicular to the axis of the mantle.

4. In a self tightening mantle for the head of a gyratory crusher, a unitary hollow body of a metal having the characteristics of manganese steel as to deformation under impact, said body having the general form of an open topped truncated cone and having an exterior generally conic crushing face and an interior generally conic head engaging face, the thickness of said body being generally uniform from top to bottom thereof, and an integrally formed locking and stress relieving element, in the form of a thread located adjacent the top of said body and extending laterally inwardly therefrom into the central aperture at the top of the body. the radial extension of said thread inwardly from the body being sufficient to permit a flexure of the thread in response to the tendency of the body to peen or deform under crushing stress, and substantially exceeding the thickness of the thread, said thread being provided with a plurality of generally radial interruptions whereby it is divided into separate sections adapted for individual flexure.

5. In a self tightening mantle for the head of a gyratory crusher, a unitary hollow body of a metal having the characteristics of manganese steel as to deformation under impact, said body having the general form of an open topped truncated cone and having an exterior generally conic crushing face and an interior generally conic head engaging face, the thickness of said body being generally uniform from top to bottom thereof, and an integrally formed locking and stress relieving element, in the form of a thread located adjacent the top of said body and extending laterally inwardly therefrom into the central aperture at the top'of the body, the radial extension of said thread inwardly from the body being suflicient to permit a fiexure of the thread in response to the tendency of the body to peen or deform under crushing stress, and substantially exceeding the thickness the thread, the inner face of said body being provided with oiIset portions adapted to receive a liner of ductile material and to prevent its rotation in relation to the mantle.

6. In a self tightening mantle for the head of a gyratory crusher, a unitary hollow body of a metal having the characteristics of manganese steel as to deformation under impact, said body having the general form of an open topped truncated cone and having an exterior generally conic crushing face and an interior generally conic head engaging face, the thickness of said body being generally uniform from top to bottom thereof, and an integrally formed locking and stress relieving element, in the form of a thread located adjacent the top of said body and extending laterally inwardly therefrom into the central aperture at the top of the body, the radial extension of said thread inwardly from the body being suiiicient to permit a ilexure of the thread in response to the tendency of the body to peen or deform under crushing stress, and substantially exceeding the thickness of the thread, the vertical dimension of said thread at its junction with the body being substantially less than the radial extension of the thread inwardly from said body, and being radially progressively inwardly reduced.

7. In a self tightening mantle for the head of a gyratory crusher, a unitary hollow body of a metal having the characteristics of manganese steel as to deformation under impact, said body having the general form of an open topped truncated cone and having an exterior generally conic crushing face and an interior generally conic head engaging face, the thickness of said body bein generally uniform from top to bottom thereof, and an integrally formed locking and stress relieving element, in the form of a thread located adjacent the top of said body and extending laterally inwardly therefrom into the central aperture at the top of the body, the radial extension of said thread inwardly from the body being suilfl-= cient to permit a flexure of the thread in response to the tendency of the body to peen or deform under crushing stress, and substantially exceeding the thickness of the thread, the vertical di mension of said thread at its junction with the body being substantially less than the radial extension of the thread inwardly from said body, the vertical dimension of said thread decreasing outwardly from its Junction with the body, the upper surface of the thread being perpendicular to the axis of the mantle.

8. In a gyratory'crusher and in combination with a generally conic head, a self tightening mantle therefor, including a unitary hollow body of metal having the characteristics of manganese steel as to deformation under impact, said body being in the form of an open topped truncated cone and having an exterior generally conic crushing face and an interior generally conic head engaging face, the thickness of said body being generally uniform from top to bottom thereof, and an integrally formed locking and stress relieving element in the form of a thread located adjacent the top of said body and extending laterally inwardly therefrom into the central aperture at the top of the body, the radial extension of said thread inwardly from the body being sufllcient to permit a flexure of the thread in response to the tendency of the body to peen under crushing stress, and substantially exceeding the thickness of the thread, and locking means on the head and including a member opposed to the upper surface of said thread, said member being normally fixed against movement in relation to the head, the pitch of said thread being opposed to the normal direction of gyration of said head, said mantle being free to rotate in relation to said head.

9. In combination, a crushing head, and means for gyrating it, a stem upwardly extending from the head, a sleeve vertically movable on said head, means for holding said sleeve against rotation in relation to said stem, including a pin penetrating an aperture in said stem and opposed apertures in said sleeve, and means for holding said pin against endwise movement, a mantle on said head free to rotate in relation to said head, a screw threaded element adjacent the top of the mantle, a lower portion of said sleeve being screw threaded in opposition thereto, the direction of pitch of said opposed threads being adapted, in response to movement of the mantle in the normal crushing operation, to tighten the opposed threads and thereby to hold the mantle firmly on the head.

10. In combination, a crushing head, and means for gyratlng it, a stem upwardly extending from the head, a sleeve vertically movable on said head, means for holding said sleeve against rotation in relation to said stem, including a pin penetrating an aperture in said stem and opposed apertures in said sleeve, and means for holdin said pin against endwise movement, including a second pin extending through said sleeve and into said first pin, a mantle on said head free to rotate in relation to said head, a screw threaded element adjacent the top of the mantle, a lower portion of said sleeve being screw threaded in opposi tion thereto, the direction of pitch of said opposed threads being adapted, in response to movement of the mantle in the normal crushin opera tion, to tighten the opposed threads and thereby to hold the mantle firmly on the head.

11. In combination, a crushing head, and means for gyrating it, a stem upwardly extending from the head, a sleeve vertically movable on said head, means for holding said sleeve against rotation in relation to said stem, means for providing a downward thrust against an upper portion of said sleeve, including a member threaded on said stem, and means for holding said threaded member against undesired rotation in relation to said stem, a mantle on said head free to rotate in relation to said head, a screw threaded element adjacent the top of the mantle, a lower portion of said sleeve being screw threaded in opposition thereto, the direction of pitch of said opposed threads being adapted, in response to movement of the mantle in the normal crushing operation,

to tighten the opposed threads and thereby to hold the mantle firmly on the head.

12. In a self-tightening mantle for the head of a gyratory crusher, a unitary hollow body of a metal having the characteristics of manganese steel as to deformation under impact, said body having an integrally formed locking and stress relieving element in the form of a thread extending inwardly from the upper edge of the body and having a radial inward extension from the body substantially exceeding the thickness of the thread, whereby the thread is free to flex in response to the tendency of the body to peen or deform under crushing stress while the mantle is in position on the head of a gyratory crusher.

13. In a self-tightening mantle for the head of being formed of a metal having the characteristics of manganese steel as to deformation under impact, a screw thread adjacent the top of the .radial inward extension of the thread being sufficient, in relation to the thickness of the thread and the material of which it is formed to permit a flexure of the thread in response to the tendency a gyratory crusher, a unitary hollow body of a metal having the characteristics of manganese steel as to deformation under impact, said body having an integrally formed locking and stress relieving element in the form of a thread extending inwardly from the upper edge of the body and having a radial inward extension from the body substantially exceeding the thickness of the thread, whereby the thread is free to flex in response to the tendency of ,the body to peen or deform under crushing stress while the mantle is in position on the head of a gyratory crusher, the thread extending about an arc of the order of 360.

14. In a self-tightening mantle for the head of a gyratory crusher, a unitary hollow body of a metal having the characteristics of manganese steel as to deformation under impact, said body having an integrally formed locking and stress relieving element in the form of a thread extending inwardly from the upper edge of the body and having a radial inward extension from the body substantially exceeding the thickness of the thread, its thickness diminishing progressively toward its inner edge, whereby the thread is free to flex in response to the tendency of the body to peen or deform under crushing stress while the mantle is in position on the head of a gyratory crusher.

15. In a gyratory crusher and in combination with a generally conic head, a self-tightening mantle therefor, including a hollow body of metal having the characteristics of manganese steel as to deformation under impact, said body having an integrally formed locking and stress relieving element in the form of a thread extending inwardly from the upper edge of the body and having a radial inward extension from the body substantially exceeding the thickness of the thread, its thickness diminishing progressively toward its inner edge, whereby the thread is free to flex in response to the tendency of the body to peen or deform under crushing stress while the mantle is in position on the head of a gyratory crusher, and locking means on the head and including a member opposed to the upper surface of said thread, said member being normally fixed against movement in relation to the head and including a thread extending outwardly from the axis of the head, said thread having a substantial clearance between its upper face and the lower face of th thread on the mantle.

16. In combination, a crushing head and means for gyrating it, a guiding stem upwardly extending fromthe head, a sleeve vertically movable on said stem, means for holding said sleeve normally against rotation and against vertical movement in relation to said stem, a mantle on said head, free to rotate in relation to said head, said mantle of the body to peen under crushing stress, the lower portion of the sleeve having a screw thread opposed to the screw thread of the mantle, the direction of pitch of the opposed threads being adapted, in response to movement of the mantle in the course of the normal crushing operation to tighten the opposed threads against each other and thereby to hold the mantle firmly on the head, said threads being in contact only at their opposed faces, the upper face of the thread on the mantle being opposed to the lower face of the thread on the sleeve.

17. The structure of claim 16 characterized by the employment of threads on the mantle and the sleeve of a length, each, of the order of 360 degrees of arc.

18. The structure of claim 16 characterized by the employment on the mantle of a thread having a length of the order of 360 degrees of arc.

19. The structure of claim 16 characterized by the employment of threads on both mantle and sleeve having opposed faces which are perpendicular, in radial cross section, to the axes of the mantle and stem, the upper face of the thread on the mantle being opposed to the lower face of the thread on the stem, the lower face of the thread on the mantle being at all times out of contact with the upper face of the thread on the stem.

20. The structure of claim 16 characterized by the employment of threads on both mantle and sleeve having opposed faces which are perpendicular, in radial cross section, to the axes of the mantle and stem, the upper face of the thread on the mantle being opposed to the lower face of the thread on the stem, the lower face of the thread on the mantle being at all times out of contact with the upper face of the thread on the stem, the non-opposed faces of each thread being tapered outwardly from the root of the thread whereby each thread is of a progressively reduced thickness laterally outwardly from its root;

21. In combination, a crushing head and means for gyratlng it, a guiding stem upwardly extending irom the head, a sleeve verticahy movable on said stem, means for holding said sleeve normally against rotation and against vertical movement in relation to said stem, a mantle on said head, free to rotate in relation to said head, said mantle being formed or a metal having the characteristics of manganese steel as to deformation under impact, a screw thread adjacent the top of the mantle and extending inwardly from the upper edge therefrom and integral with the mantle, said, thread'being of reduced thickness laterally inwardly from its root, the radial inward extension of the thread being sunicient, in relation to the thickness of the thread and the material of which it is formed to permit a flexure of the thread in response to the tendency of the body to peen under crushing stress, the lower portion of the sleeve having a screw thread opposed to the screw thread of the mantle,.the direction of pitch of the opposed threads being adapted, in response to movement of the mantle in the course of the normal against each other and thereby to hold the mantle firmly on the head. said threads being in contact only at their opposed faces, the upper face or the thread on the mantle being opposed to the lower face or the thread on the sleeve.

22. A wearing member for gyratory crushers and the like which comprises a body of metal having the characteristics of manganese steel as to peening under impact, said body being in the form or a. hollow truncated cone, and having an inte grally formed thread extending inwardly from an 10 body to peen under crushing stress, said thread extending about an arc of the order or 360 degrees.

OSCAR C. GRUENDER. 

